I’m not sure if you’ve seen this thread yet, but it looks very similar to the issue described in KNOWN ISSUE: Tilesets not loading in packaged Unreal apps. This solution seems to be more or less solvable by downloading the correct root certificates from AWS, but the root cause is more likely something to do with the way Unreal resolves SSL certificates. Would you mind running this sample project and sharing the log? That will help us nail down exactly what’s going on. If you’re in a hurry, installing the SSL root certificate seems to be the solution (but please run the sample project and share the logs beforehand, if possible!)